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Kennedy/Jenks Consultants
<br /> There has been no prior subsurface investigation of OU-2. For purposes of the RI, the OU was
<br /> subdivided into five AOIs based on former uses (see Figure 3):
<br /> • AOI 4— Ponds. This area is comprised of the three former ponds that are currently
<br /> backfilled with soil and concrete debris.
<br /> • AOI 5 — Oil Tank. This area includes the former large oil tank and adjacent facilities,
<br /> including an oil pump house, grass swale, railroad tracks, and various oil drains, oil
<br /> pipes, air pipes, and water pipes.
<br /> • AOI 6 — Roundhouse. Improvements in this area included the turntable, two
<br /> roundhouse structures, engine pit, oil sump, tool house, store house, railroad tracks and
<br /> associated oil pipes.
<br /> • AOI 7 — Support. This was an area of varied support facilities, including settling tanks,
<br /> pump houses, lumber shed, store houses, storage tanks, power house, personnel
<br /> offices/housing, railroad tracks, and various oil pipes, air pipes, and water pipes.
<br /> • AOI 8 —Track. Railroad tracks are the main feature in this area.
<br /> 1.4.3 Operable Unit 3
<br /> OU-3 consists of approximately two acres at the southwestern corner of the Railyard, bounded
<br /> on the north by the railroad right-of-way dividing OU-3 from OU-4, on the east by another
<br /> railroad right-of-way separating OU-3 from OU-2, on the south by Fourth Street, and on the west
<br /> ' by Central Avenue (Figure 2).
<br /> The City is interested in developing OU-3 and OU-4 into a multi-modal transportation hub. On
<br /> behalf of the City, Geocon Consultants, Inc. (Geocon) performed subsurface characterization
<br /> activities in OU-3 and OU-4 in February 2005 (Geocon 2005). The field activities included:
<br /> • excavating ten exploratory trenches, with the collection and analysis of soil samples
<br /> • advancing eight soil borings, with the collection and analysis of soil and reconnaissance
<br /> groundwater samples
<br /> • potholing along the Kinder Morgan petroleum pipeline
<br /> A total of 26 soil samples were collected from the trenches and submitted for analysis of metals,
<br /> TPHg, TPHd, TPHmo, BTEX, organochlorine pesticides, VOCs and chlorinated herbicides. Nine
<br /> reconnaissance groundwater samples were analyzed for TPHg, TPHd, TPHmo, BTEX, VOCs
<br /> and semivolatile organic compounds (SVOCs).
<br /> Arsenic concentrations in the soil samples collected by Geocon in OU-3 and OU-4 ranged from
<br /> less than 1.0 mg/kg to 67 mg/kg, with higher concentrations typically observed in the surface
<br /> soil samples. Total lead concentrations in the soil samples collected by Geocon in OU-3 and
<br /> OU-4 ranged from 8.2 mg/kg to 2,000 mg/kg, with the shallow soil samples containing higher
<br /> concentrations of lead than the deeper soil samples.
<br /> DRAFT Phase I Remedial Investigation Report Page 7
<br /> Former Tracy Railyard, Tracy, California
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